Transition to EMDS_* environment variables

[acordonez]

Since these are the EMDS standards, the environment variables should refer to EMDS rather than specifically to CMEC or MDTF. This will promote interoperability and consistency.

[acordonez]

For reference, these are the currently defined keys in the standard:

Key	Definition
CMEC_CODE_DIR MDTF_POD_CODE_DIR	The directory where the DEM’s code can be found
CMEC_OBS_DATA MDTF_POD_OBS_DATA	The directory where the relevant observational data can be found.
CMEC_MODEL_DATA MDTF_MODEL_DATA	The directory containing the model input data. If autocurated metadata has been generated, it can be found in the file autocurator.json in the root directory.
CMEC_WK_DIR MDTF_POD_WK_DIR	The working directory for output from the DEM.
MDTF_CASENAME MDTF_FIRSTYR MDTF_LASTYR	(optional) Variables used by MDTF PODs for labeling plots.
CMEC_DEBUG MDTF_DEBUG	(optional) If set to 1 then the DEM should output more verbose logging information to help with debugging.
CMEC_SAVE_NC MDTF_SAVE_NC	(optional) If set to 0 then the DEM should skip any steps where raw output data is saved in netCDF format.

[acordonez]

Here is a proposed set of new environment variables:

Key	Definition
EMDS_CODE_DIR	The directory where the DEM’s code can be found
EMDS_OBS_DATA	The directory where the relevant observational data can be found.
EMDS_MODEL_DATA	The directory containing the model input data. If autocurated metadata has been generated, it can be found in the file autocurator.json in the root directory.
EMDS_WK_DIR	The working directory for output from the DEM.
EMDS_CASENAME EMDS_FIRSTYR EMDS_LASTYR	(optional) Variables used by MDTF PODs for labeling plots.
EMDS_DEBUG	(optional) If set to 1 then the DEM should output more verbose logging information to help with debugging.
EMDS_SAVE_NC	(optional) If set to 0 then the DEM should skip any steps where raw output data is saved in netCDF format.